JP2007089149A - Method and apparatus for switching network modes - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively select wireless network communication characteristics. <P>SOLUTION: In the method for operating a wireless network including a plurality of nodes, the network can operate in a plurality of network modes and is capable of switching the mode among different network modes, while each network mode indicates an operating scheme of the network in which a plurality of network parameters are selected so that the network satisfies, as a whole, the desired operation characteristics corresponding to such a network mode. Meanwhile, the network is capable of switching the operation mode to the target network mode, satisfying the different desired operation characteristics from the present network mode using one of a plurality of switching methods, while respective switching method has different switching characteristics. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method and apparatus for switching a network mode, in particular a wireless network mode.

  The network must generally allow data communication between any nodes. The characteristics required for this communication depend on the specific environment in which the communication takes place, and the application requires reliable data transfer, short latency or energy efficient communication between network nodes.

  In a wireless sensor network (hereinafter sometimes referred to as WSN), the pattern of data communication is different from that of the conventional network, and the WSN application is different from the conventional application. First, WSN applications and their communication requests are often known prior to the execution time of the WSN application. Second, communication in WSN is usually characterized by communication centered on so-called data processing. In particular, sensor data (eg, from multiple sources) is aggregated, transformed, or otherwise processed before being transferred using a multi-hop path.

  However, there are a variety of ways to organize network traffic in a wireless network, and the only possibility is to aggregate data and transfer the aggregated data. Under certain circumstances, instead of using data aggregation, other than network communication that can use direct communication between individual nodes or aggregate under "Quality of Service (QoS)" It may be preferable to change the characteristic parameter.

  Traditional network protocols that provide selectable communication characteristics use QoS (Quality of Service) parameters that map the parameters to a single point-to-point link. Thus, the application can select the appropriate QoS parameters for each connection. However, a standard application in a WSN (Wireless Sensor Network) contains many single nodes and thus contains many possible and practical connections between them. Setting the desired characteristics for all connection requirements is time consuming and will introduce a lot of overhead on the network.

  In view of the foregoing, one object of the present invention is to enable effective selection of communication characteristics in a wireless network.

  According to one embodiment, a method for operating a wireless network including a plurality of nodes, wherein the network is capable of operating in a plurality of network modes and switching between different network modes. Each network mode represents an operation scheme of the network in which a plurality of network parameters are selected such that the network as a whole satisfies desired operation characteristics corresponding to the network mode. And the plurality of network modes include a high-speed network mode in which the network operates at high speed and another energy efficiency mode in which the network operates in an energy efficient manner. One of a number of switching methods can be used to switch from the current network mode to a target network mode that meets different desired operating characteristics, each switching method having a different switching characteristic. Selecting a switching method for switching to the target mode such that the switching characteristic of the switching method matches a desired operation characteristic of the target network mode; and Switching from the current network mode to the target network mode, wherein one of the plurality of switching methods is energy-saving compared to other switching methods. -An energy-saving switching method that performs switching efficiently, and another one of the plurality of switching methods is a high-speed switching method that performs switching at a higher speed than other switching methods, and the target network mode is When the energy efficiency mode is selected, an energy efficient switching method is selected from the plurality of switching methods, and when the target network mode is the high speed mode, the high speed switching method is selected from the plurality of switching methods. A method is provided.

  According to one embodiment, a method for operating a wireless network including a plurality of nodes, wherein the network is capable of operating in a plurality of network modes and switching between different network modes. Each network mode represents an operation scheme of the network in which a plurality of network parameters are selected such that the network as a whole satisfies desired operation characteristics corresponding to the network mode. The plurality of network modes include a high-speed network mode in which the network operates at high speed and another reliable mode in which the network operates reliably. The network includes a plurality of network modes. One of the switching methods can be used to switch from the current network mode to a target network mode that meets different desired operating characteristics, each switching method having different switching characteristics, Selecting a switching method for switching to the target mode such that the switching characteristic of the switching method matches a desired operation characteristic of the target network mode, and using the selected switching method. Switching from the current network mode to the target network mode, wherein one of the plurality of switching methods is faster than other switching methods. The switching method is a high-speed switching method, and another one of the plurality of switching methods is a reliable switching method that performs switching more reliably than other switching methods, and the target network mode is the high-speed switching method. When the mode is a mode, the fast switching method is selected from the plurality of switching methods, and when the target network mode is the reliable mode, the reliable switching method is selected from the plurality of switching methods. Is provided.

  According to one embodiment, a method for operating a wireless network including a plurality of nodes, wherein the network is capable of operating in a plurality of network modes and switching between different network modes. Each network mode represents an operation scheme of the network in which a plurality of network parameters are selected such that the network as a whole satisfies desired operation characteristics corresponding to the network mode. The plurality of network modes include an energy-saving network mode in which the network operates while saving energy, and another reliable mode in which the network operates reliably. The network is capable of switching from the current network mode to a target network mode that meets different desired operating characteristics using one of a plurality of switching methods, each switching method having a different switching characteristic. Selecting a switching method for switching to the target mode such that the switching characteristic of the switching method matches a desired operation characteristic of the target network mode; and the selected Switching from the current network mode to the target network mode using a switching method, wherein one of the plurality of switching methods includes other switching methods. An energy-saving switching method that performs switching more efficiently than a switching method, and another one of the switching methods is a reliable switching method that performs switching that is more reliable than other switching methods. When the target network mode is the energy saving mode, the energy saving switching method is selected from the plurality of switching methods, and when the target network mode is the reliable mode, the reliable switching method is the plurality of switching methods. A method is provided that is selected from methods.

  This enables a particularly effective method of adjusting network parameters through the network mode and adaptive switching between network modes. Instead of considering every single connection between individual nodes, it is advantageous to set the entire network (or part of it) to a desired mode called network mode. A network mode can be considered as having a characteristic that makes communication of the network a basis of operation when a pattern, method, or network is in a certain “network mode”. The network mode is, for example, an “energy efficient” mode, a “reliable” mode, or a fast or “low latency” mode. With a mode that represents a desired overall characteristic or overall nature of network communication, individual network parameters such as network topology, routing protocol, etc., can be adapted so that the overall characteristics of network operation match the desired mode. Selected in a mode.

  Several predefined “network modes” are provided, and instead of establishing individual connections with the desired QoS parameters for individual connections in the network, there is an application (or another external trigger) A certain network mode with characteristics can be requested. Thus, an entire network or a set of network nodes belonging to an application, or a portion of the network responsible for a task, is one step, eliminating the need to establish every single route to itself. Can be set to network mode. This network mode can itself consist of several high-level network parameters or characteristics such as “high speed data transfer” or “use of redundant routes”. This network maps this mode and its corresponding high-level network parameters to link parameters and node parameters to provide the required communication operations. By using different network parameters, certain network modes can be defined. These modes offer the application the possibility to achieve optimized network operation (depending on the application's requirements) by invoking the most suitable network mode under a given environment.

  By providing a plurality of switching methods, it is possible to select a switching method for switching to a target network mode that matches the target network mode with respect to its characteristics, or to a target network mode according to the target mode. In other words, this switching method “predicts” the target network mode in a sense, or its characteristics match the characteristics of the target network mode in the most likely way (among the provided switching methods). At least selected to do. This selection is thus made to minimize the negative effects of switching that negate the “purpose” or “characteristic” of the target mode, given the available switching methods.

  According to one embodiment, one of the plurality of network modes is an energy saving mode, and the selected switching method is a method of performing energy efficient switching to other available switching methods. Thereby, this switching method already anticipates the purpose of the target mode, i.e. energy savings, and already fulfills to some extent.

  According to a further embodiment, one of these multiple network modes is a fast mode, and the selected switching method is such that the switching is performed faster compared to other available switching methods. Selected. This makes it possible to meet at least part of the rapid response time that is the purpose of the fast mode already during switching, or at least that the switching is performed in a manner that is contrary to the purpose of the target mode. There is no.

  According to a further embodiment, one of these multiple network modes is a reliable mode, and the selected switching method is a method of performing reliable switching to other available switching methods. . This makes it possible to provide to some extent the purpose of reliability intended by the target mode already during switching.

  According to a further embodiment, the plurality of switching methods includes selectable switching propagation methods for propagating the switching signal through the nodes of the network. Different switching propagation methods may also have different characteristics that match the characteristics of the target network mode to different extents. By properly selecting the switching propagation mode, the target mode requirements can already be taken into account during switching.

  According to a further embodiment, the plurality of switching methods includes a plurality of selectable switching trigger methods for triggering switching of the network mode from the current mode to the target mode. Different switching trigger methods may also be adapted to the target network mode to different extents, therefore, by properly selecting the switching trigger method, it is already due to the characteristics and requirements of the target mode during the switching process. It can also serve a purpose.

  According to a further embodiment, the plurality of switching methods includes selectable node role switching methods for switching the role of a node in the network from its current role to a role according to the target network mode. By providing different role switching methods, the new role of the node can be adopted in the most appropriate way under a given environment.

  According to a further embodiment, the selection of the switching method is further based on context information representing the status of the network, node or environment in addition to the characteristics of the target network mode. By using context information in addition to the mere characteristics of the target mode, switching can be applied to a given environment in a much more sophisticated manner.

  According to a further embodiment, the selection of a network mode switching method includes one or more of a selection of a switching propagation method, a selection of a switching trigger method, and a selection of a node role switching method. Combining the selection of switching propagation method, switching trigger method and node role switching method allows an adaptive execution for switching from one network mode to another network mode.

  According to a further embodiment, each network mode specifies for each node a role of the node in a network mode and specifies a set of parameters further indicating one or more of a switching propagation method and a switching trigger method. Yes.

  By assigning a set of parameters to each network mode that defines the switching propagation method and the switching trigger method, the network mode is changed as each parameter is subsequently called by reference to the stored lookup table. And a relatively easy implementation of different methods modified accordingly. Instead of a lookup table, other means can be used to determine the switching propagation method and the switching trigger method, for example a rule based approach can be used as well.

  According to one embodiment, a network node for operating a wireless network including a plurality of nodes, wherein the network is capable of operating in a plurality of network modes, and the node can be operated between different network modes. Each network mode is a network of which a plurality of network parameters are selected such that the network as a whole satisfies the desired operational characteristics corresponding to that network mode. The plurality of network modes include a high-speed network mode in which the network operates at high speed and another energy efficiency mode in which the network operates in an energy efficient manner. The network node is capable of switching from a current network mode to a target network mode that satisfies different desired operation characteristics using one of a plurality of switching methods, each switching method having a different switching characteristic. A selection module for selecting the switching method for switching to the target mode such that the switching characteristic of the switching method matches a desired operation characteristic of the target network mode. And a switching module for switching from the current network mode to the target network mode using the selected switching method, One of the switching methods is an energy-saving switching method that performs switching more efficiently than other switching methods, and another one of the plurality of switching methods is faster than the other switching methods. When the target network mode is the energy efficiency mode, the selection module selects an energy efficient switching method from the plurality of switching methods, and the target network mode is the high speed switching method for performing switching. When in fast mode, the selection module provides a network node in which the fast switching method is selected from the plurality of switching methods.

  According to one embodiment, one of the plurality of switching methods is a high-speed switching method that performs switching more efficiently than other switching methods, and another one of the plurality of switching methods is: Reliable switching method that performs switching at high speed compared to other switching methods, and when the target network mode is the high-speed mode, the high-speed switching method is selected from the plurality of switching methods by the selection module, When the target network mode is the reliable mode, the reliable switching method is selected from the plurality of switching methods by the selection module.

  According to one embodiment, one of the plurality of switching methods is an energy-saving switching method that performs switching with energy efficiency compared to other switching methods, and another one of the plurality of switching methods is A reliable switching method that performs switching at a higher speed than other switching methods. When the target network mode is the energy saving mode, an energy efficient switching method is selected from the plurality of switching methods by the selection module. When selected and the target network mode is the reliable mode, the reliable switching method is selected from the plurality of switching methods by the selection module.

  Thereby, when the network has an energy saving mode, a high-speed mode, and a reliable mode as network modes, the switching process to the target network mode can be adapted.

  The network node can be used to implement an adaptive switching method according to an embodiment of the present invention, as described above.

  According to one embodiment, the target network mode is an energy saving mode, and the selected switching method is performed by the following mechanism: a node performs the switching based on a timeout, before starting a new mode. A method for performing energy efficient switching to one or more of the following: breaking old mode operation, using an effective routing protocol such as multicast.

  Using a timeout as a trigger for switching to energy efficiency mode allows an internal determination based on the timeout whether switching criteria are met, so that individual switching should be done. The switching can be performed without having to notify the other nodes. Furthermore, not only does the node need to receive a message, it does not need to send a switching propagation message. This saves energy and thereby complies with the target mode requirements. Breaking or terminating the operation of the old mode before starting a new mode, and using an effective routing mechanism such as multicast is similar to the fact that switching is performed effectively. Can contribute.

  According to one embodiment, the target network mode is a fast mode, and the selected switching method has the following mechanism: the switching message received by the node is forwarded without delay, the switching message is fast A fast route or fast routing mechanism, switching message propagation is performed independently of actual switching, and fast switching to the mode using one of the following: It is a method to execute.

  By forwarding switching messages without delay, it is possible to propagate switching messages through the network at high speed, thereby increasing the overall speed of switching. In order to avoid delays that may be caused by waiting for actual switching, propagation is preferably performed independently of actual switching.

  According to one embodiment, the target network mode is a reliable mode, and the selected switching method has the following mechanism: a switching message propagated by the node is at least one of a plurality of routes or redundant routes. Using one or more of the following: redirection using the switch, repetitive transfer of the switching message, operating the old mode at least until the start of the operation of the new mode In this method, switching to the mode is performed. This ensures that the propagation of switching messages is performed to match the characteristics of the target mode. Redundant routes or multiple routes and repetitive forwarding of switching messages improve the reliability of the switching process. Similarly, operating the old mode at least until the new mode of operation starts contributes to the reliability of the switching process.

  According to one embodiment, the switching propagation method for propagating switching through the network is performed independently of the actual switching of the nodes. This allows criteria that are independent of the criteria used for the actual switching to be applied to the propagation of the switching, and also independent of the actual switching state. It is also possible to propagate switching messages that can facilitate all of the switching at high speed.

  According to one embodiment, the wireless network is a wireless sensor network.

  In the following, the present invention will be described using typical embodiments.

  In the first embodiment of the invention, the network mode is used in connection with a wireless sensor network (WSN). A typical application using these network modes is a medical application as shown in FIG. The network includes a plurality of sensors that are partially located on the patient's body and also partially around the room and possibly around other rooms (not shown). Yes.

  In FIG. 1, the three individual diagrams show three typical network modes in the case of such a scenario. The mode shown on the left is a “normal mode” used in the normal state for monitoring physical functions. This overall characteristic is that it is an energy efficient mode. The mode shown in the center is a “health alert” mode where, for some reason, for example, the patient's physical condition suddenly deteriorates, a higher level of monitoring of physical function is required without delay compared to the normal mode. is there. Therefore, its overall characteristics are high speed and low latency. The right side of FIG. 1 is preferred to have fast and reliable distributed information because there is a fire somewhere in the area, so its overall characteristics are “reliable ( "Fire Alert Mode" that can be described as "Reliable".

  In summary, the energy efficiency mode can be mapped to a physical monitoring state in which measurement data about the patient's health status is collected periodically, while the direct mode requires less delay in data transfer, It is possible to map to a fire alert state in which a node may fail with a high probability.

  In the following, the three different modes will be described in somewhat more detail by describing the individual network parameters that result in the desired overall characteristics or behavior.

The normal mode is an energy efficiency mode. Normal mode is intended to extend the life of the network. This can be achieved by applying an appropriate scheme to save energy. For example, individual nodes can select an appropriate sleep cycle, and the network uses an energy efficient routing method. Considering the network parameters, the normal mode is characterized as follows:
The first is to allow a node energy saving mode (eg, sleep) by allowing slow responsiveness and speed.
Second, it is possible to aggregate data.
Third, the network topology can be optimized.

The direct mode is an alert mode. This direct mode relaxes energy constraints, where energy saving is not the purpose of direct mode. Although the WSN is supposed to save as much energy as possible inside the normal mode, the main purpose in the direct mode is to provide communication with low latency. The direct mode is characterized as follows.
The first is to avoid using the node's power saving sleep mode.
Second, there is no data aggregation.
The third is to connect directly to the least intermediate (farthest but reachable) node.
The third is to transfer data with a minimum delay.

The redundancy mode is an alarm mode. In redundant mode, energy constraints are further relaxed. In addition to no aggregation, parameter redundant data transfer is introduced. Thus, data transfer is extremely reliable and fast. In this redundancy mode, the following network parameters are set.
The first is to avoid using the node's power saving sleep mode.
Second, there is no data aggregation.
Third, redundant data transfer is possible.
The fourth is to use redundant routing paths.

  These network parameters specify how the network node operates. Each network mode designates a certain set of network parameters that define how it operates in a network mode for n individual nodes.

  By introducing a network mode, certain parts or regions of the network can be made common characteristics with respect to communication and data processing. Because different network modes result in different network characteristics, the network mode must be changed when a situation (the “situation” or “context” in which this network operates) or an application requires a different network operation. This means that network parameters must be changed for a certain node. However, the operation of switching the network mode affects the network operation itself because the mode change must be communicated to the individual nodes. Additional messages may be required to initiate switching to another mode, and the network must distribute the activation of this switching. In addition, sensor nodes may be in use to determine switching criteria and the like. Some switching types can even disrupt network services by reconfiguring individual communication links or even the topology of the entire network.

  According to an embodiment of the present invention, a plurality of switching methods are provided for the network. Each switching method has “overall characteristics” and the characteristics that best match the characteristics of the target network node when the network switches from the current network mode to the new “target” network mode. The switching method to switch to is selected.

  According to an embodiment of the present invention, it is envisaged that the network mode should be switched from the current network mode where the current node characteristics are not energy-saving to the network mode that is an energy-saving mode. The In such a case, a switching method having energy saving characteristics is selected from a plurality of possible switching methods. This avoids the switching method itself being inconsistent with the switching intent, i.e. saving energy.

  According to yet another embodiment, it is envisaged that switching should be performed to a target network mode with particularly low latency (or fast response time). In such cases, if the switching method itself causes service disruption or is otherwise not fast, it would be contrary to the purpose of switching. In such a case, if different switching methods are provided, one switching can be realized at a higher speed. When the other switching is performed in a more gradual and slower manner that may result in service interruption due to switching to a target network mode with the characteristic of low latency, the characteristics meet this objective. A suitable switching method is selected, ie a switching method that performs switching in a more rapid manner.

  In summary, the network can be operated so that the characteristics that best match the characteristics of the target network mode are selected among a plurality of switching methods. Can be described by a single term describing the characteristics of the target network mode (eg, a single characteristic such as “energy saving”, “low latency”, or “high reliability”, or an overall characteristic) Depending on the), a corresponding switching method for switching to such a target network mode is selected and the switching negative side effects that may contradict the characteristics of the target mode are selected to be minimal The For example, in the example described above, ie when the network mode characteristics are “energy saving”, “low latency”, and “high reliability”, three corresponding switching methods are provided, the first method being It is energy saving, the second method is fast, and the third method is reliable. Depending on the target network mode to which the network is to be switched, an appropriate switching method is selected so that its characteristics match those of the target network mode.

  To implement this embodiment, store network modes (corresponding to respective sets of network parameters) and switching methods, eg save respective sets of network parameters corresponding to respective modes in respective network nodes, respectively Can be pre-defined by further storing a set of switching parameters that define a switching method for each available switching method in a given node. Each target network mode can then be assigned to a corresponding switching method that is invoked when switching to the target network mode is required.

  FIG. 2 schematically illustrates mode switching according to an embodiment of the present invention. In operation 200, a triggering event responsible for initiating network mode switching occurs. This event may be a request by the application that the network switches its mode, or an “external” event where the parameter measured by the WSN sensor exceeds the threshold, thereby requesting switching of the network mode It may be. In operation 210, the target network mode is then determined, for example when the trigger event is a parameter measurement, the target network mode looks up a lookup table or maps a parameter measurement to the corresponding target network mode. And can be determined by applying a more sophisticated algorithm. When the trigger event in operation 200 is a request by an application, the target network mode has already been explicitly requested by the application, in which case operation 210 can be omitted.

  Once the target network mode is determined, at operation 220, the corresponding switching method whose characteristics are most appropriate for the target network mode is selected. Again, this can be done by looking up a lookup table or by any more sophisticated decision algorithm. Then, in operation 230, the selected switching method is performed to switch from the current network mode to the target network mode.

  Hereinafter, a procedure for network mode switching according to an embodiment of the present invention will be described in more detail. This procedure is performed at every node in the network and starts with one first node and switches all nodes to the new mode. Thereby, an individual node can determine how to reach its new mode based on the current mode, target mode and available context information. Available context information may include information such as available battery power, processing power, or connectivity (whether it can connect to some other node in the network).

  A switching process for switching from one network mode to another network mode includes several features. A network mode actually corresponds to the fact that each node in the network operates according to the current network mode, in other words that the node has a status that reflects the current network mode. . When this network mode is changed, each individual node must be given information about the change to be performed, for example by a trigger message, and then this node can change its new function (change its status). ) Must be assumed according to the new network mode. Furthermore, typically network mode switching not only assumes that the node assumes its new functionality, but also the network mode itself that receives the trigger message performs mode switching to other network modes. It is also necessary to deliver information that it should. Even the delivery of this trigger message (or switching message) can be performed independently of whether the node has already changed its function to the new network mode.

  This will now be described in more detail in connection with FIG. According to the current network mode, a node has a corresponding status, as shown in element 300 of FIG. This status corresponds to the actual network mode and further corresponds to a setting with internal parameters (referred to above as network parameters) inside the node that reflects this status. One such network parameter may be the role of a node in the network, for example, the node may be a source (only transmitting signals and not receiving), a sink (only receiving signals). Or an aggregation node that receives signals from some nodes and forwards them to one or more other nodes. The network parameter may further represent whether the node is in a standby state (sleep mode) or in an operating state. In addition to such network parameters that represent the manner of operation in a network in normal communication in a mode, there may be other parameters that represent the node's manner of operation for switching, referred to as switching parameters. The switching parameter can represent what type of trigger (eg, external trigger or internal trigger) is allowed to initiate mode switching. For example, when a multi-trigger signal is needed to trigger mode switching, or when only a single trigger event is sufficient, yet another switching parameter can represent sensitivity to the trigger signal. Furthermore, there may be a switching parameter that represents how the switching signal is propagated through the network.

  Before returning to FIG. 3, first, some switching parameters related to the characteristics of the switching method will be described in more detail.

The switching parameters used can include:
The first is switching sensitivity. This parameter represents how to react to a trigger event that triggers mode switching. The switching of the reaction in the switching event may be performed immediately in response to the first trigger event or may wait for some trigger events to match or accumulate.
The second is to set a new mode. This new network mode may be set in advance while the old network mode is still operating, or the new network mode may be set after the old network mode is over.
The third is a node role change procedure. This can define how to change transport routes, communication characteristics (eg, bandwidth), and aggregation mechanisms in the network. Changes in one mode may include a new route configured through which the node should communicate, which further includes redundancy (from the source to the aggregation node or from the normal node via a redundant path). You need to change the function of the node (such as node). These changes in the role of the node will be configured so that no or minimal changes are required in the network, thereby preventing communication breakdown or disruption . Such a change can be referred to as “soft node role switching”. In contrast, a new role can be established from the earliest stages where in some cases a more optimal solution is derived. This can be referred to as “hard node role switching”.
The fourth is whether an explicit trigger or an implicit trigger is used. An explicit trigger message is a method for transferring and resending a message for switching to another mode.
The fifth is a trigger with no implicit message. This is a method of setting a timer for retreating to another mode.

Now, with reference to FIG. 3, a switching procedure according to an embodiment of the present invention will be described. The following procedure for mode switching is performed by all nodes in the network. All nodes are in a state defined by the following network parameters.
The first is the network mode.
The second is the role in the network mode (for example, aggregation node, source or sink).
Third, the processing status is active (processing state or communication state) or passive (sleep state or idle state).
The state is additionally defined by the following switching parameter.
The first is a set of allowed triggers (for example, activation in communication request, timeout trigger for switching back to normal mode, etc.).
The second is trigger sensitivity (single trigger, multi-trigger).
The third is a communication partner.

  The nodes are performing certain tasks (corresponding to their role in network mode) or are sleeping until they receive a valid trigger condition. If activation and processing is required, a trigger event initiates a procedure for mode switching.

This procedure may include the following operations that will be described with reference to FIG.
First, at operation 305, the node detects a trigger condition (single trigger, additional trigger, self trigger, partner trigger).
Second, if the trigger is sufficient, switching is initiated (operation 310 in FIG. 3), otherwise it waits for an additional trigger (step 1).
Third, a new role is determined within the node (operation 310 in FIG. 3). This new role may be calculated in advance, may be defined in advance, or may be determined by a protocol algorithm that depends on the trigger signal. The determination of the new role may include first determining the target network mode. This determination may be based on a trigger signal, for example a sensor value in this case. Once the target network mode is determined, its role in the target network mode needs to be determined. In one embodiment, the role of the node is predefined for each possible network mode and a set of network parameters is predefined for each possible target mode. However, according to yet another embodiment, it is also possible for the network node to assume additional criteria, for example applications that require mode switching depending on the trigger signal.
Fourth, once a new role in the target network mode is determined, the node must adopt that new role (operation 320). This may include setting several status parameters that reflect the status of the node and need to follow the new role of the node. The following parameters (network parameters and switching parameters) can receive new settings in this procedure.
First, it is a role parameter that defines the role of a node (for example, source, sink, aggregation node, forwarding node, redundancy base point, etc.) in that mode.
Next is the processing status parameter. For example, it represents whether it is active (processing state or communication state) or passive (sleep state or idle state).
The next is to adapt to the allowed triggers. That is, another new mode from the newly adopted mode (eg, explicit or implicit trigger, activation in communication request (yes or no), timeout trigger to switch back to a given target mode, etc.) ) To define another set of allowed triggers that can trigger another switching.
Next is trigger sensitivity (single trigger, multi-trigger).
Next is a timer for a timeout condition (depending on the type of trigger), for example in the case of a trigger event.
Next is the communication partner.
In addition to simply setting the parameters, the node then needs to adopt its new role (eg, aggregation node, forwarding node, redundancy base point, etc.) by operating according to the target network mode.
Fifth, because switching in network mode requires switching of individual nodes in the network, switching information must be distributed or propagated throughout the network. This is schematically shown in action 330. Trigger propagation can be performed in different ways with different trigger propagation characteristics. For example, for reliable trigger propagation, signal distribution methods such as flooding or broadcasting can be used. This can be used when switching to reliable network mode or redundant network mode. For fast trigger propagation, proactive routing can be used. Proactive routing here means that there is no need to determine or establish a new path before propagating the trigger message. This means that although the propagation of switching messages does not need to follow an optimal route, it is fast and a new communication path can be determined during propagation. This is particularly suitable for switching to a network mode that is fast and has low latency. For switching to energy efficient mode, energy efficient trigger propagation methods such as multicast or cluster based routing can be used.
Sixth, after switching across the network is complete, the procedure returns to the top and waits for a new trigger event (operation 300).

  In the above description, network mode switching has several components: switching trigger, actual switching or node role change itself (how the node adopts its new role), and network-wide triggering. Propagation (or switching) is included. These three components can be viewed as one another and constitute a switching method with each other, and each of these three components can be implemented in multiple ways. This is schematically shown in FIG. FIG. 4 shows that adaptive switching methods that result in different switching methods having different switching characteristics may include different triggering methods and different trigger propagation methods, each having different characteristics. . Adaptive switching methods can be implemented by selecting a mode trigger method and a trigger propagation method whose characteristics match those of the target network. In addition, the adaptive switching method can also be implemented by selecting an appropriate node role switching method, as further illustrated in FIG.

  Different triggering methods can be implemented by setting different sets of triggering parameters at each node of the network. Similarly, different trigger propagation methods can be implemented by setting different sets of trigger propagation parameters at each node of the network. Each target network mode may be designated with a corresponding set of trigger parameters and trigger propagation parameters stored at each network node. In addition, when switching to a target network mode is performed by receiving a trigger message, the node that should perform the switching searches its repository and obtains the appropriate trigger and trigger propagation parameters. And operate accordingly.

  The different node role switching method shown in FIG. 4 is either a hard role switching where the old role is discarded and a new role is established from the beginning, or the node whose role is to be changed replaces the old role with the new role. And then when the new role is fully operational, it can be implemented by selecting either soft role switching that switches completely to the new role and discards the old role.

  For example, a node that is changed from one network mode to another network mode must change its communication path. In such a case, this would be done in a “hard way” by discarding the old communication path and then establishing a new communication path from scratch. While this may be an energy saving, it can lead to service disruption and data packet loss. To prevent these effects, it can instead be performed in a “soft way”, such as by setting up a new communication path while maintaining the old communication path. This can prevent packet loss. However, it requires additional energy and additional network resources such as additional signaling bandwidth. Therefore, depending on the target mode, an appropriate node role changing mechanism can be selected accordingly.

  However, in addition to the effects due to the target mode, the selection may also be affected by context parameters that represent additional information to represent the state of the node or network or its function. The selection of the node role switching method (hard or soft switching) may be further based on such context information in addition to the target mode. For example, the battery status can be used as an additional criterion, and the selection process can save energy over soft switching when the battery status represents less battery power available. Therefore, hard switching can be selected. On the other hand, when the available battery power is sufficient, the soft switching choice will be determined. Additional context information parameters that can take into account decisions about node role switching methods may include, for example, available processing power.

  As described above, the node role change may include a routing path change. This is true, for example, when changing from the direct (high speed) mode to the normal mode. The reason is, for example, that some nodes act as aggregation nodes in the normal mode, while all nodes transfer data directly without intermediate aggregation nodes in the direct mode. In general, network mode switching may include a topology change (communication path change) in the network. This is also true when switching is either going into or out of redundancy mode. The reason is that in this case switching involves establishing or destroying redundant routing paths that can be realized by different node role switching methods.

  Furthermore, there may be a difference between performing node role switching in a “soft” manner and in a “hard” manner. Soft switching means that a new communication path is established while the old communication path is still operating to prevent latency and loss of data packets. An alternative (or additional) variant of soft node role switching is to store the received data until a new communication path is established and the stored data can be transferred up to this moment. It may be included.

  However, under certain circumstances, hard switching where a new communication path is established from the beginning after the old communication path is discarded may be preferred. This is preferable from the viewpoint of energy consumption. This is because it eliminates the need for maintenance management or providing two communication paths simultaneously. Furthermore, for example, when the target mode is the redundancy mode, there may be an additional requirement (situation requirement). For example, a change to redundant mode may include partitioning the network into different clusters, and (additional) requirements for switching node roles are that the new redundant communication path is different for different clusters. Or via even different cluster headers. In such a case, it may be preferable to create a new communication path from the beginning. This is because it is easier to ensure that the two communication paths go through different clusters in the network or through different cluster headers.

  In the previous example of network clustering in redundant mode, a combination of hard switching and soft switching can also be performed. For example, as far as establishing a new communication path is concerned, "hard switching" is performed, in other words, the communication path used after node role switching is completely configured from the beginning, independent of existing communication paths. . However, discarding an old communication path can be performed in a “soft” manner so that the old communication path is discarded only after a new communication path is established.

  In other words, when the change of the communication path is included in the node role change, at least one of establishment of a new communication path or destruction of the old communication path may be included. Both features, establishment of a new communication path and abandonment of an old communication path can be performed in a “soft” or “hard” manner. “Soft” establishment of a new communication path means that an old communication path is maintained and a new communication path is additionally established. Hard establishment of a new communication path means that a new communication path is established from the beginning independently of the existing communication path and without depending on its use. Regarding the destruction of existing communication paths, the "hard" method means that the path is destroyed independently of whether a new path has already been established, while the "soft" method Means that the old communication path is maintained until a new communication path is established.

  Yet another feature of “soft” node role switching is that it employs the use of the intermediate state of the node when switching its role. This will help avoid communication disruptions or packet loss. Such an intermediate state may include the use of a place to store the received data that is transferred after the final state is reached (node role switching is finished).

  In the embodiment described in conjunction with FIG. 3, it has been described that trigger propagation is performed after an individual node adopts its new role, but according to one embodiment, adoption of a new role of node and propagation of a trigger. Note that can be performed independently of each other. According to one embodiment, for example, the trigger signal may already have been propagated by the node first, even though the node has not yet adopted a new role (by changing its network parameters). It will be possible.

  A general advantage of the above embodiment of the method for switching between network modes is that it enables efficient switching by taking into account the characteristics of the new network mode. These characteristics determine network operation in overall conditions such as energy efficiency, data delay, reliability, and response time. In this way, according to one embodiment, performing switching to an energy efficient network mode with loose requirements on data delay (again achieves optimal aggregation to save energy again) Along with the possibility of reconfiguring the network topology, it results in a choice of switching methods based on timeouts (reducing communication work and thereby saving energy). In contrast, if the new network mode requires high speed data communication, a switching method is selected when switching is message based (which reduces switching time). Furthermore, when energy efficiency is not a criterion, the selected switching method can employ long-distance hops instead of communication only with very close neighbors (which are fast but consume energy). Appropriate selection of such a switching method allows adaptation of the switching of the procedure to the characteristics of the new network mode by already meeting the requirements of the new mode during the switching process.

In the following, yet another embodiment of the present invention will be described, but its network operation is three network modes similar to those already described, normal mode with energy efficient characteristics, low delay or latency. It is possible to map to a “direct mode” having the characteristics possessed and a redundant mode having high reliability as the characteristics. These basic characteristics in the three network modes result in corresponding requirements regarding the switching method employed to switch between the network modes. These switching requirements list the essential characteristics (which must be met when switching to a network mode) and irrelevant characteristics that are of little importance and need not be met during switching: Is summarized in the table.

The general procedure for switching has already been described. Depending on the target mode in which switching is performed, different switching methods can be employed by using different options. Thereby, the switching method is adapted to the characteristics of the target network mode, for example, switching to energy saving mode (normal mode) is energy efficient and also to direct mode (high speed mode). Can be selected so that switching to the redundant mode is reliable and switching to the redundant mode is reliable. In the next embodiment, the following options are available to implement different switching methods.
* The first group is a different switching signal propagation method.
(1) Reliable propagation (broadcasting, flooding)
(2) Bandwidth efficient propagation (multicast, cluster-based routing)
(3) High-speed propagation (proactive routing, that is, propagation of trigger message while switching is executed)
* The second group is a different switching trigger method.
(1) A reliable trigger that takes into account possible malfunctions of the sensor node by appropriately adapting the trigger sensitivity (eg some nodes should detect the trigger event and actually switch Trigger criteria should be met for a longer period to trigger)
(2) Reliable triggers taking into account unreliable wireless links (for example, by repeatedly sending switching signal messages several times)
(3) Fast triggering by adapting trigger sensitivity (eg, whenever a node detects a trigger event, that node always sends a trigger signal message)
(4) An energy efficient trigger by using a timeout as a trigger for switching. Thereby, unnecessary communication can be avoided and energy can be saved.

  A switching method for switching to the target network mode is selected such that when an option is selected, its characteristics match those of the target network mode.

  In the following, further embodiments for implementing different switching methods for switching between different network modes will be described.

Switching from the redundant mode to another mode means deleting the redundant communication path that has been used in the redundant mode in order to obtain high reliability. In the case of switching to energy efficient normal mode, it is preferable that a new energy efficient topology is additionally configured (for example to allow signal aggregation by energy saving aggregation nodes). . To save energy, costly links will be removed even before new communication paths are provided by the new topology, which may cause disruption of communication at this stage by prioritizing energy acquisition be able to. In contrast, when uninterrupted communication (direct mode and redundant mode) is required for the target mode, it is preferable to first configure a new communication path before deleting the old communication path. These detailed steps performed when switching between network modes are shown in the following table.

  For each node, the trigger is either external or internal (eg, a sensor value received from another node, or a “switching message”, or an internal timeout). Which trigger is valid can be set by an internal parameter of the node. If this trigger parameter is set to require an external trigger message, or "switching message", the node receiving such a message needs to propagate it throughout the network. This propagation can be done in different ways. One way is to adjust the time between receipt and transmission of a trigger (or switching) message. Another way is to change the prerequisites for sending the trigger message. For example, when the trigger event must be very reliable (eg, considering possible sensor malfunctions), the node may repeat the same trigger message several times before forwarding the trigger message. I will wait for the repetition. In contrast, when a quick response to a trigger event is desired (eg in case of an emergency), the trigger message will be further forwarded by the node whenever a trigger message is received. In the case of an external trigger, several sources can send trigger messages simultaneously. In this case, complex trigger conditions (eg, multi-trigger matches, considering changes in trigger reliability from different sources, etc.) can be defined. Next, based on a decision algorithm that uses this information as a parameter, it is determined whether to switch the node, when to switch the node, and when to propagate the trigger message.

  However, in other aspects, trigger propagation can be done in different ways according to the target network mode requirements. For example, the propagation protocol for switching to normal (energy efficient) mode in one embodiment is preferably simple, and generates little extra traffic in the network. preferable. The frequency of trigger message repetitions should be low to save energy. The time between trigger event detection and propagation may be long. This can be achieved by using a trigger method based on timeout to return to normal mode.

  Propagation protocols to switch to direct mode (fast mode) or redundant mode (reliable mode) must be very reliable. In these cases, trigger messages are often (repeatedly) and transmitted at short time intervals (increased traffic is allowed using broadcasts, redundant messages, etc.). Since the time between trigger detection and propagation must be short, each received trigger message immediately triggers the propagation of the trigger message by the node that received the message.

  As described above, the possible options for triggering and trigger propagation in this embodiment are adapted to the target network mode and selected accordingly.

  In the following, a more specific example of the switching method according to an embodiment of the present invention will be described, but switching between the normal (energy efficient) mode and the direct (high speed) mode will be described in more detail. .

  In the upper left of FIG. 5, a WSN for monitoring the human health state in the normal mode is shown. Several sensors measure the physical function that establishes an aggregate group. All of the data is aggregated by one of them (body sensor 2), and the aggregated data is transmitted to the storage node. This aggregate topology reduces energy consumption by reducing the range in which messages need to be transmitted. When the monitoring result is stored in the storage node, and the physical condition represented by the data of the body sensor is to be alarmed (or an explicit alarm message is issued from a certain sensor), In order to notify a nurse or doctor, the storage node notifies an alarm node equipped with an alarm bell, for example. The normal data flow from the body sensor 1 and body sensor 2 to the body sensor 3 and from them to the storage node is indicated by solid arrows.

  In the upper right of FIG. 5, a sensor (Sensor 1) detects a dangerous situation (eg, an increase in pulse or the like), and based on that, determines that the situation has been changed to a certain state. Has been shown to do. This state is the state where the network mode should be switched from normal mode to a more appropriate alert mode (or “direct mode”) for this state to monitor the physical condition more frequently and more directly .

  The node then changes its role in the network according to the network mode in which switching is to be performed, which here means that the node communicates directly with the storage node. In addition to the change to direct communication, this node adapts its timeout parameters (those that set the timeout for reversion to normal mode), and the node responds to propagate switching Sending the switching message immediately provides information to the new counterpart of the switching to be performed. This is indicated by the dashed arrow leading from sensor 1 to the storage node in the upper right of FIG. A broken line surrounding the sensor 1 indicates that the operation mode has already been switched, while a solid line surrounded by another node indicates that the operation mode is still in the normal mode.

  In the lower right of FIG. 5, the storage node responds to repeated switching messages and is triggered to a new mode (direct mode) and accordingly to its counterpart (a trigger has been sent because it has already been switched). Provides information about the remaining body sensors 2 and 3 and alarm nodes (except those). This propagation of the switching message is schematically indicated by a dashed arrow pointing from the storage node to its communication partner. According to these switching messages, all sensor nodes will also switch the mode to direct mode and will now send directly to the storage node (see lower left of FIG. 5). Here, the nodes in the direct state are indicated by broken lines surrounding these nodes.

  As long as the dangerous situation continues, the responsive sensor node (body sensor 1) continues to refresh the mode which has the effect of repeatedly updating the timeout by repeatedly propagating the switching message, so that its sensor data is Keep the network in direct mode as long as necessary.

  When no dangerous situation is detected by any sensor node, the timeout is no longer refreshed and ends (lower left in FIG. 5). Each node is triggered by a timeout event that has an effect on the corresponding node that switches back to normal mode. Not all nodes switch back at the same time, because the timing of the switching messages that affected the timeout setting at different nodes at different times is different. Some nodes still try to communicate directly, but others have already switched to normal mode. This switchback has an effect that each node assumes a new role assigned to a normal node such as the body sensor 2 having a function that the aggregation node tries to aggregate once the timeout is finished. This can lead to communication disruptions during the timeout period when timeout events occur. As soon as all nodes switch back, the monitoring application begins to function correctly in normal mode. This is done as shown in the upper left of FIG.

  Hereinafter, a network node according to an embodiment of the present invention will be described in more detail with reference to FIG. The node 630 is provided with an operation module 610 that performs the functions of the network node by communicating with the wireless network 620 via the wireless interface 630 and the wireless link 640. The network node may operate according to one of a plurality of network modes and switch from one network mode to another network mode under the control of the switching module 650. The switching module 650 is connected to a switching selection module 660, which can select one of a plurality of switching methods in which switching is performed by the module 650. The switching selection module 660 receives an external signal 670 that triggers switching to a new target network mode. Here, it should be mentioned that the signal 670 is physically received from another node via the wireless link 640. Therefore, the signal 670 and the arrows representing it in FIG. 6 should be understood as representing logical connections that can be physically implemented by the wireless link 640.

  As shown in FIG. 6, the trigger signal 670 is also an internally generated trigger signal generated in response to some measurement measured by a sensor (eg, a temperature sensor) provided at the node. Also good. The switching selection module 660 can evaluate whether the signal 660 can actually be considered a valid trigger signal, and if so, the corresponding target network mode is determined by the module 660. Module 660 may then select a switching method for switching to the target network mode from the available switching methods so that the selected switching method best matches the characteristics of the target mode. Subsequently, the result of the selection can be transferred to a switching module 650 that subsequently performs the actual switching according to the selected method.

  The functions of the switching module 650 and the switching selection module 660 are suitably programmed to perform their respective operations, such as a microprocessor or DSP that has an appropriate interface to receive the signal 670. It can be implemented by a programmable device. The operation module 610 may also include a microprocessor that controls its functions, and according to one embodiment, the microprocessor of the operation module 610 may perform the functions of the switching selection module 660. it can. Furthermore, the operational module 610 includes a wireless interface 630 such as a transmitter, receiver or transceiver that can be implemented as a component for establishing a wireless link, and an appropriate control including the microprocessor or DSP described above. Electronic equipment.

  In one embodiment, once switching is performed by a node 600, propagation of a switching message (switching trigger signal) across the network can be performed by that node 600. A switching message can then be sent over the wireless link 640 that also provides information to other nodes that switching to the target mode should be performed.

  However, according to yet another embodiment, the propagation of switching messages across the network can be performed independently of the actual switching. For such purposes, the switching selection module 620 may comprise a switching propagation module 625 as schematically illustrated in FIG. 6, which further propagates switching messages. It is. For such purposes, it may be directly connected to the wireless interface 630 and forwards a switching propagation message over the wireless link 640 when the trigger message is received by the node 660 by the wireless interface 630. can do. By such a mechanism, switching propagation can be performed independently of actual switching.

  Switching propagation can be performed in different ways depending on certain criteria, as already explained in connection with the previously described embodiments. To that end, the switching propagation module 625 performs some logic to determine whether the criteria for propagating the switching message are met (eg, received the required number of trigger messages), and so on. If so, a switching message is propagated. This decision also includes a decision regarding that the switching message is propagated, eg, whether it is propagated using multicast transmission, broadcast or unicast. Such a determination can also be made based on the desired characteristics of the target mode, for example multicast may be more energy efficient than unicast. Therefore, in the case of switching to an energy saving mode, multicast would be the preferred mode of switching message propagation, for example.

  More generally, according to one embodiment, the switching module is adapted to switch by different switching trigger methods and by the different switching propagation methods described in connection with some of the previous embodiments. It is configured. Therefore, the switching selection module can be configured to select the switching trigger method and the switching propagation method according to the target network mode. Thereby, switching propagation, actual switching, and switching trigger can be controlled, and can be executed independently of each other.

  According to some embodiments of the invention, the switching selection module 620, the switching module 610, and the partial operation module can be executed by one or more microprocessors. The microprocessor is programmed to perform switching method selection, switching trigger method selection, and switching propagation method selection in connection with the previously described embodiments.

  One skilled in the art will appreciate that some of the embodiments described thus far can be implemented in hardware, software, or a combination of software and hardware. The modules described in connection with the embodiments of the present invention may be implemented in whole or in part by a microprocessor or computer appropriately programmed to operate according to the methods described in connection with the embodiments of the present invention. be able to.

  According to some embodiments of the invention, it is stored in a data carrier or captured by some physical means such as a recording medium or transmission link when stored in a computer and stored in some other way. A computer program capable of operating a computer according to the above-described embodiment of the present invention is provided.

1 illustrates a network environment in which certain embodiments according to the invention may be implemented. 3 is a flowchart illustrating an embodiment according to the present invention. 6 is a flowchart according to another embodiment of the present invention. Fig. 4 schematically shows different switching methods according to an embodiment of the invention. Fig. 4 schematically illustrates switching between network modes according to an embodiment of the invention. 1 schematically shows a configuration of a network mode according to an embodiment of the present invention.

Explanation of symbols

600 Node 610 Operation module 620 Wireless network 625 Switching propagation module 630 Wireless interface 640 Wireless link 650 Switching module 660 Switching selection module 670 Signal

Claims (21)

A method for operating a wireless network including a plurality of nodes, comprising:
The network is operable in a plurality of network modes and capable of switching between different network modes,
Each network mode represents an operation scheme of the network in which a plurality of network parameters are selected such that the network as a whole satisfies desired operation characteristics corresponding to the network mode;
The plurality of network modes include a high-speed network mode in which the network operates at high speed and another energy efficiency mode in which the network operates in an energy efficient manner,
The network is capable of switching from a current network mode to a target network mode that meets different desired operational characteristics using one of a plurality of switching methods;
Each switching method has different switching characteristics,
Selecting a switching method for switching to the target mode such that the switching characteristic of the switching method matches a desired operational characteristic of the target network mode;
Switching from the current network mode to the target network mode using the selected switching method; and
One of the plurality of switching methods is an energy-saving switching method that performs switching more efficiently than other switching methods;
Another one of the plurality of switching methods is a high-speed switching method that performs switching at a higher speed than other switching methods,
When the target network mode is the energy efficiency mode, an energy efficient switching method is selected from the plurality of switching methods,
When the target network mode is the high speed mode, the high speed switching method is selected from the plurality of switching methods.
Method. A method for operating a wireless network including a plurality of nodes, comprising:
The network is operable in a plurality of network modes and capable of switching between different network modes,
Each network mode represents an operation scheme of the network in which a plurality of network parameters are selected such that the network as a whole satisfies desired operation characteristics corresponding to the network mode;
The plurality of network modes include a high-speed network mode in which the network operates at high speed and another reliable mode in which the network operates in a reliable manner.
The network is capable of switching from a current network mode to a target network mode that meets different desired operational characteristics using one of a plurality of switching methods;
Each switching method has different switching characteristics,
Selecting a switching method for switching to the target mode such that the switching characteristic of the switching method matches a desired operational characteristic of the target network mode;
Switching from the current network mode to the target network mode using the selected switching method; and
One of the plurality of switching methods is a high-speed switching method that performs switching at a higher speed than other switching methods,
Another one of the plurality of switching methods is a reliable switching method that performs switching more reliably than other switching methods,
When the target network mode is the fast mode, the fast switching method is selected from the plurality of switching methods;
When the target network mode is the reliable mode, the reliable switching method is selected from the plurality of switching methods.
Method. A method for operating a wireless network including a plurality of nodes, comprising:
The network is operable in a plurality of network modes and capable of switching between different network modes,
Each network mode represents an operation scheme of the network in which a plurality of network parameters are selected such that the network as a whole satisfies desired operation characteristics corresponding to the network mode;
The plurality of network modes include an energy-saving network mode in which the network operates while saving energy, and another reliable mode in which the network operates in a reliable manner.
The network is capable of switching from a current network mode to a target network mode that meets different desired operational characteristics using one of a plurality of switching methods;
Each switching method has different switching characteristics,
Selecting a switching method for switching to the target mode such that the switching characteristic of the switching method matches a desired operational characteristic of the target network mode;
Switching from the current network mode to the target network mode using the selected switching method; and
One of the plurality of switching methods is an energy-saving switching method that performs switching more efficiently than other switching methods;
Another one of the plurality of switching methods is a reliable switching method that performs switching more reliably than other switching methods,
When the target network mode is the energy saving mode, the energy saving switching method is selected from the plurality of switching methods;
When the target network mode is the reliable mode, the reliable switching method is selected from the plurality of switching methods.
Method.   The method according to any one of claims 1 to 3, wherein the plurality of switching methods comprises a plurality of selectable switching propagation methods for propagating a switching signal through the nodes in the network.   The method according to any one of claims 1 to 4, wherein the plurality of switching methods comprises a plurality of selectable switching trigger methods for triggering switching of a network mode from a current mode to a target mode. .   The plurality of switching methods include a plurality of selectable node role switching methods for switching a role of a node in the network from a current role to a role according to the target network mode. 6. The method according to any one of 5 above.   The selection of a switching method is further based on context information representing a status of the network, the node or the environment in addition to the characteristics of the target network mode. the method of. The selection of a network mode switching method is:
Selecting a switching propagation method;
Selecting a switching trigger method;
The method according to claim 1, comprising one or more of selecting a node role switching method. Each network mode indicates to each node the role of that node in a network mode and as an element of the network switching method,
Switching propagation method;
A switching trigger method;
The method according to claim 1, wherein a set of parameters further indicating one or more of the node role switching method is designated. A network node for operating a wireless network including a plurality of nodes,
The network is operable in a plurality of network modes;
The node is capable of switching between different network modes;
Each network mode represents an operation scheme of the network in which a plurality of network parameters are selected such that the network as a whole satisfies desired operation characteristics corresponding to the network mode;
The plurality of network modes include a high-speed network mode in which the network operates at high speed and another energy efficiency mode in which the network operates in an energy efficient manner,
The network node is capable of switching from a current network mode to a target network mode that satisfies different desired operational characteristics using one of a plurality of switching methods;
Each switching method has different switching characteristics,
A selection module for selecting the switching method for switching to the target mode such that the switching characteristic of the switching method matches a desired operation characteristic of the target network mode;
A switching module for switching from the current network mode to the target network mode using the selected switching method;
One of the plurality of switching methods is an energy-saving switching method that performs switching more efficiently than other switching methods;
Another one of the plurality of switching methods is a high-speed switching method that performs switching at a higher speed than other switching methods,
When the target network mode is the energy efficiency mode, the selection module selects an energy efficient switching method from the plurality of switching methods,
When the target network mode is the fast mode, the fast switching method is selected from the plurality of switching methods by the selection module.
Network node. A network node for operating a wireless network including a plurality of nodes,
The network is operable in a plurality of network modes;
The node is capable of switching between different network modes;
Each network mode represents an operation scheme of the network in which a plurality of network parameters are selected such that the network as a whole satisfies desired operation characteristics corresponding to the network mode;
The plurality of network modes include a high-speed network mode in which the network operates at high speed and another reliable mode in which the network operates in a reliable manner.
The network node is capable of switching from a current network mode to a target network mode that satisfies different desired operational characteristics using one of a plurality of switching methods;
Each switching method has different switching characteristics,
A selection module for selecting the switching method for switching to the target mode such that the switching characteristic of the switching method matches a desired operation characteristic of the target network mode;
A switching module for switching from the current network mode to the target network mode using the selected switching method;
One of the plurality of switching methods is a high-speed switching method that performs switching energy-efficiently compared to other switching methods,
Another one of the plurality of switching methods is a reliable switching method that performs switching at a higher speed than other switching methods,
When the target network mode is the fast mode, the fast switching method is selected from the plurality of switching methods by the selection module;
When the target network mode is the reliable mode, the reliable switching method is selected from the plurality of switching methods by the selection module.
Network node. A network node for operating a wireless network including a plurality of nodes,
The network is operable in a plurality of network modes;
The node is capable of switching between different network modes;
Each network mode represents an operation scheme of the network in which a plurality of network parameters are selected such that the network as a whole satisfies desired operation characteristics corresponding to the network mode;
The plurality of network modes include a reliable network mode in which the network operates in a reliable manner and another energy saving mode in which the network operates with energy saving,
The network node is capable of switching from a current network mode to a target network mode that satisfies different desired operational characteristics using one of a plurality of switching methods;
Each switching method has different switching characteristics,
A selection module for selecting the switching method for switching to the target mode such that the switching characteristic of the switching method matches a desired operation characteristic of the target network mode;
A switching module for switching from the current network mode to the target network mode using the selected switching method;
One of the plurality of switching methods is an energy-saving switching method that performs switching more efficiently than other switching methods;
Another one of the plurality of switching methods is a reliable switching method that performs switching at a higher speed than other switching methods,
When the target network mode is the energy saving mode, the selection module selects an energy efficient switching method from the plurality of switching methods;
When the target network mode is the reliable mode, the reliable switching method is selected from the plurality of switching methods by the selection module.
Network node. The plurality of switching methods include:
A plurality of selectable switching propagation methods for propagating switching signals through the nodes of the network; and / or
A plurality of selectable switching trigger methods for triggering said switching of the network mode from the current mode to the target mode; and / or
The node role switching method according to any one of claims 10 to 12, further comprising a plurality of selectable node role switching methods for switching the role of a node in the network from a current role to a role according to the target network mode. Network nodes. The choice of a network mode switching method is
Selecting a switching propagation method;
Selecting a switching trigger method; and
The network node according to claim 10, comprising one or more of selecting a node role switching method.   The selection of the switching method is further based on context information representing a status of the network, the node, or the environment in addition to the characteristics of the target network mode. Network node. Each network mode indicates to each node the role of the node in a network mode,
Switching propagation method;
A switching trigger method;
The network node according to any one of claims 10 to 15, which specifies a set of parameters further indicating one or more of node role switching methods. Each network mode indicates to each node the role of that node in a network mode and as an element of the network switching method,
Switching propagation method;
A switching trigger method;
The network node according to any one of claims 10 to 16, which specifies a set of parameters further indicating one or more of node role switching methods. The target network mode is an energy saving mode, and the selected switching method is as a mechanism:
The node performs the switching based on a timeout;
Breaking the behavior of the old mode before starting the new mode,
18. The method of any one of claims 10 to 17, wherein the method is an energy efficient method of switching to the mode using one or more of using an effective routing protocol such as multicast. The described network node. One of the network modes is the fast mode, and the selected switching method is as a mechanism:
The switching message received by the node is forwarded without delay;
Switching messages are forwarded using fast routes or fast routing mechanisms;
18. The method of performing switching to the mode at high speed using one or more of propagation of switching messages performed independently of actual switching. The network node according to any one of the above. One of the network modes is the reliable mode, and the selected switching method is as a mechanism:
Switching messages propagated by the node are forwarded using either or both of multiple routes and redundant routes;
The switching message is propagated repeatedly;
18. The method of performing switching to the mode in a reliable manner using one or more of operating the old mode until at least the new mode begins to operate. The network node according to any one of the above.   The network node according to any one of claims 11 to 19, wherein the switching propagation method for propagating the switching through the network is performed independently of the actual switching of the node. Or the method as described in any one of Claims 1-10.